O029 The Impact of Adherence to Specific Components of CBT for Insomnia on Treatment Outcomes

Abstract Introduction CBT-I requires significant behavioural change. A recent systematic review found there are surprisingly few associations between adherence to that behaviour change and outcomes. Prior studies examined adherence over the entire course of treatment, however, the role of adherence may change throughout therapy. We examined the effect of adherence to Sleep Restriction (SR) and Stimulus Control (SC) using the recently proposed two-stage Build-Maintain Model of CBT-I. Methods 83 participants underwent 7 weeks of therapist-led CBT-I. 78 initiated SR (age: 48.0±14.3, 57.7%F). Treatment was divided into “Build” (initial phase of SR, building sleep debt) and “Maintain” (starting the first week sleep opportunity increased) stages of therapy. Analyses examined the impact of adherence to SR (deviation from bed/wake times, naps) and SC (wake time-in-bed during daytime, overnight, and after final awakening) and stage of treatment on diary-based sleep efficiency (SE) and Insomnia Severity Index (ISI). Results Adherence to morning SC predicted both greater SE (regardless of the stage) and lower ISI (specifically during Maintain stage). Fewer average minutes napping predicted lower ISI scores, regardless of stage. Discussion Adherence to morning SC (i.e., getting out of bed right away after final awakening) and adherence to the no-nap rule of SR were associated with better CBT-I treatment outcomes. Surprisingly, adherence to neither the prescribed bed time nor wake time in SR were associated with treatment outcomes. While adherence to some aspects of CBT-I appear related to outcomes, more work needs to be conducted to determine the measure(s) of adherence most predictive of treatment outcomes.